Think-aloud (or thinking aloud) protocol (also talk-aloud protocol) is a protocol used to gather data in usability testing in product design and development, in psychology and a range of social sciences (e.g., reading, writing, translation research, decision making, and process tracing).
The method has a host of advantages. Most important, it serves as a window on the soul, letting you discover what users really think about your design. In particular, you hear their misconceptions, which usually turn into actionable redesign recommendations: when users misinterpret design elements, you need to change them. Even better, you usually learn why users guess wrong about some parts of the UI and why they find others easy to use.
- Participants verbalize what they are doing and thinking as they complete a task
- This is among the most common evaluative methods in the usability community, revealing aspects of an interface that delight, confuse, or frustrate.
- It asks people to articulate what they are doing, thinking, or feeling as they complete a set of tasks that align with their realistic day-to-day goals.
- Concurrent think-aloud is most common, asking the participant to work through tasks while articulating what he or she is doing, thinking, and feeling.
- Retrospective think-aloud asks participants to complete a task in silence and then comment on their processes as they watch a recorded replay of their experience. This can provide additional insight into participant reasoning, intentions, and strategy.
- The method can be used on low- or high-fidelity prototypes, physical artefacts that require assembly, devices to be synchronized, or customized products.
The thinking aloud method also offers the benefits of being:
- Cheap. No special equipment is needed; you simply sit next to a user and take notes as he or she talks. It takes about a day to collect data from a handful of users, which is all that’s needed for the most important insights.
- Robust. Most people are poor facilitators and don’t run the study exactly according to the proper methodology. But, unless you blatantly bias users by putting words into their mouths, you’ll still get reasonably good findings, even from a poorly run study. In contrast, quantitative (statistical) usability studies are ripe with methodology problems and the smallest mistake can doom a study and make the findings directly misleading. Quant studies are also much more expensive.
- Flexible. You can use the method at any stage in the development lifecycle, from early paper prototypes to fully implemented, running systems. Thinking aloud is particularly suited for Agile projects. You can use this method to evaluate any type of user interface with any form of technology (although it’s a bit tricky to use thinking aloud with speech interfaces. Websites, software applications, intranets, consumer products, enterprise software, mobile design: doesn’t matter — thinking aloud addresses them all, because we rely on the users doing the thinking.
- Convincing. The most hard-boiled developers, arrogant designers, and tight-fisted executives usually soften up when they get direct exposure to how customers think about their work. Getting the rest of your team (and management) to sit in on a few thinking-aloud sessions doesn’t take a lot of their time and is the best way to motivate them to pay attention to usability.
- Easy to learn.